Otis Technology O12-CU Copper Remover (4-Ounce) Effective copper removal solvent by Otis Technology Ammonia and petroleum-free, completely biodegradable and environmentally safe Easily removes copper fouling from all parts of your firearm Safe for all types of metal Prevents rust and corrosion Removes copper fouling with ease Prevents rust and corrosion for long-lasting barrel protection Safe on all gun metals